joshua022

iTrader: (12)

I have a 5.3/4l60 in my 68c10 and the transmission just started acting up..

Whenever its under a load going up hill between like 40-50mph it jumps in and out of overdrive.

Stock converter, stock ECM no tune whatsoever.

Didn't seem to have issues before I wired up my auto meter gauges, and the speedo ties into the VSS and the PCM speed output. Could this have something to do with it.

I just got it home and checked the fluid and its not even on the stick, I will get it topped off in the am and recheck it. I've only had the truck like 2weeks.

I've done lots of searching on here and got a variety of answers for this same complaint.

Thanks
Joshua

SparkyJJO

iTrader: (11)

Is the 4L60E stock?

What year is that transmission?

There is a common TCC issue on the 4L60E that can cause that, and it is worse in hot weather. It's a relatively easy to fix if you don't mind messing with the valve body.

joshua022

iTrader: (12)

Yes it's stock, and out of a 2001 Tahoe.

I've heard of that issue but was hoping the low fluid would fix it...lol

SparkyJJO

iTrader: (11)

Well definitely try the fluid first. Not all 4L60E's suffer from the problem, though all have the same flaw that can lead to it.

If you want more kit info PM me as there is an ebay seller that I've used that has literally everything you need aside from fluid in a nice kit (new plate, seals, and a few worthwhile extras).

jimmyblue

iTrader: (11)

Misfiring, most likely. You could see it on a scan
tool if you log the right PIDs.

joshua022

iTrader: (12)

really?? I need to wire in an OBD port before I can really check for any of that.

Also it seems to go away if I give it enough gas to keep it in 3rd and then pulls strong, so I came up with an idea to see if temporarily its possible to fool the computer into thinking the tow/haul button has been pressed??



was 2.5qts low, no signs of a leak though.

and it still does it.

SparkyJJO

iTrader: (11)

You sure it is in 3rd or is it just still in 4th popping out of TC lockup?

joshua022

iTrader: (12)

It jumps up and down several hundred rpms (~500) so I don't think its just the TC unlocking and locking.

but without being able to plug into it I cannot know for sure.

01SuperSport

iTrader: (7)

My car did that a couple times before it completely went out and had to be rebuilt

mrvedit

Wow, you really need to hook up the OBD port on your swap. I suspect there are a bunch of codes pending that will pinpoint your problem.
IMO the OBD port is the most useful automotive invention since the piston.

SparkyJJO

iTrader: (11)

My 98 would do that at highway speeds when it was popping the TCC on and off, until it stopped engaging at all when warm. Which, by the way, that trans from my 98 is now in my 99 after the pretty simple fix and it has been perfect.

joshua022

iTrader: (12)

No issue after all, it was a "dirty" signal where I had tapped into the VSS. went straight to the PCM and it runs great.

mrvedit

Thanks for the update and glad you figured it out. The PCM is sensitive to any problems with the sensors.

ss performance

iTrader: (17)

another item to check is the pedal posistion sensor (or throttle posistion sensor) Not sure in your situation but if they start going bad it can cause simular problems.